The present invention relates to a semiconductor device, a video display system, and a method of processing a signal.
Recently, a conventional semiconductor device has been used as a controller for displaying an image such as a video image on a display unit such as a display panel. In the conventional semiconductor device, signals having different frequencies are input thereto as a signal for displaying the image on the display unit. For example, in a conventional vehicle mount video system, the conventional semiconductor device is configured to receive signals having different frequencies from various devices including a camera (a monitor) such as a backup camera for smooth parking, a car navigation device connected to a smartphone, and the like.
In the conventional vehicle mount video system, it may be configured to reduce EMI (Electro Magnetic Interference). For example, Patent Reference has disclosed a conventional vehicle mount video system provided with a PLL with a frequency dispersion function as a system clock, thereby reducing EMI.
Patent Reference: Japanese Patent Publication No. 2003-150143
In the conventional vehicle mount video system disclosed in Patent Reference, when the signals are input from the backup camera, the device, and the like, a processing unit such as a CPU (Central Processing Unit) disposed outside the conventional vehicle mount video system performs specific image processing on the signals, so that an image is displayed on the display unit. In this case, the conventional vehicle mount video system receives the signals on which the processing unit such as the CPU disposed outside the conventional vehicle mount video system performs the specific image processing.
As described above, the conventional vehicle mount video system receives the various signals. In some occasion, the signals may be displayed on the display unit without the frequency dispersion processing. For example, in the conventional vehicle mount video system disclosed in Patent Reference, an analog signal is displayed on the display unit without the frequency dispersion processing. Accordingly, it is difficult to sufficiently reduce EMI.
In view of the problems of the conventional semiconductor device described above, an object of the present invention is to provide a semiconductor device, a video display system, and a method of processing a signal capable of sufficiently reducing EMI regardless of a type of input signal.
Further objects and advantages of the invention will be apparent from the following description of the invention.